The use of fluorides is a major factor toward preventing cavities. Maintaining therapeutic levels of fluoride over time and reducing baseline risk is essential to fluoride's efficacy. However, current topical fluoride treatments are readily soluble in saliva, quickly dissolving and exhausting their efficacy within 24 hours. Notwithstanding, a traditional application of 1.23% acidulated phosphate fluoride (APF) gel in a disposable tray can result in fluoride ingestion of between 14 and 31 mg. “One-minute” topical fluoride gels may reduce exposure time and incidence of ingestion. However, most fluoride depositions on sound enamel do not last more than 24 hours. This has been found true in both in vitro and in vivo applications and is attributed to the release of loosely bound fluoride on enamel.
Currently available diffusion methods are inadequate for effectively transporting therapeutic agents deeper than 20 μm into enamel, at least partially due to the fact that enamel has a 100-250 μm thick surface layer with very low permeability. Therefore, there exists a need for more efficient delivery methods and systems to introduce active agents into intraoral structures.